For attaching an integrated circuit on a chip in such a way that it is in electrical contact with a circuitry pattern, methods are known for direct attachment of the chip by flip-chip technology. Alternatively, the chip can be attached in such a way that a separate structural part, onto whose surface the chip is attached, is connected to the smart label.
A method is known from the publication U.S. Pat. No. 5,810,959, in which a substrate and a silicon chip are attached by means of an anisotropic conductive thermosetting adhesive by using heat and pressure.
Publication U.S. Pat. No. 5,918,113 discloses a method, in which an anisotropic conductive adhesive is applied onto a circuit board. The adhesive contains a thermoplastic or thermosetting resin and conductive powder dispersed therein. The adhesive layer is softened, and a semiconductor chip is adhered to it on application of heat and pressure.
From the publication U.S. Pat. No. 5,918,363, a method is known in which integrated circuits formed on a wafer are tested to determine whether they are functional. An underfill is applied on the functional integrated circuits, and the chips are separated from each other. The underfill can contain a thermoplastic substance. After this, the silicon chips are connected to their location of use in such a way that the underfill is spread around the electric connections.
From the publication U.S. Pat. No. 5,936,847, an electronic circuit is known in which there is a non-conductive polymer layer forming an underfill between a substrate and a chip. The polymer layer is provided with openings for electrical contacts. The substrate is also provided with openings, through which a conductive polymer is injected to form an electrical contact between the substrate and the chip.
The publication U.S. Pat. No. 6,040,630 discloses a connection for a chip which can also be disconnected, if necessary. On a substrate having a circuitry pattern formed on the substrate, a thermoplastic film is positioned, the film exposing the bumps of the chip. The thermoplastic film forms an underfill for the chip, and when the film is heated, it connects the chip and the circuitry pattern.
A method is known from the publication U.S. Pat. No. 6,077,382, in which an anisotropic conductive thermosetting adhesive is placed on a circuit board, and the circuit board is heated to a temperature which is lower than the setting temperature of the adhesive. A semiconductor chip is placed in its position and attached by means of heat and pressure.
Methods based on flip-chip technology have for example the following disadvantages:                the production line is complicated, expensive and inconvenient in view of further development, because all the operations are integrated on the same line, and        the placement of the chip on the smart label requires that the tool used has a long path and also that the chip is positioned very precisely in the correct location.        
The smart label can also be provided with a separate structural part comprising an integrated circuit on a chip, attached on a film material.
The electrical contact between the integrated circuit on the chip and the circuitry pattern of the smart label is formed so that the film material of the separate structural part is impregnated with a conductive layer which is connected to the chip and which layer is brought into contact with the circuitry pattern in connection with the manufacture of the smart label by connecting both ends of the strip-like structural part to the circuitry pattern. That is, the structural part is off the smart label in the area between its ends. The structural part is attached to that side of the smart label on whose opposite side the circuit pattern is located so that the chip comes against the smart label.
The above-mentioned methods involve for example the following problems:                the techniques of attaching the structural part are unsophisticated and complex,        the materials presently used require long processing times, for which reason a significant difference is not achieved in the production rate when compared with flip-chip technology,        due to the slow processes, lines for single process steps become relatively complex and expensive,        the mechanical techniques for connecting the structural parts, such as crimp connections, restrict the material choices and may also cause problems of reliability,        in some existing smart labels, the distance between the structural part and the circuitry pattern and simultaneously the distance between the integrated circuit on the chip and the circuitry pattern are changed by bending, because the structural part is not wholly attached to the smart label, wherein the stray capacitance affecting the frequency of the electrical oscillating circuit is changed, and        the smart label has a relatively thick construction, which is disadvantageous in further processing steps.        